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Mitochondrial encephalomyopathy: elevated visual cortex lactate unresponsive to photic stimulation--a localized
T Kuwabara1, H Watanabe, K Tanaka
1Department of Neurology, Niigata University, Japan.
Neurology
|March 1, 1994
Summary
Mitochondrial encephalomyopathy patients with Kearns-Sayre syndrome (KSS) exhibit elevated lactate in the visual cortex. Unlike healthy individuals, KSS patients show no significant lactate increase during photic stimulation (PS).
Area of Science:
- Neuroscience
- Biochemistry
- Medical Imaging
Background:
- Mitochondrial encephalomyopathies are a group of debilitating neuromuscular disorders.
- Kearns-Sayre syndrome (KSS) is a rare mitochondrial disease affecting multiple organ systems.
- Metabolic alterations in the visual cortex are implicated in neurological dysfunction.
Purpose of the Study:
- To investigate metabolic changes in the visual cortex of KSS patients using magnetic resonance spectroscopy (MRS).
- To compare lactate levels in KSS patients and healthy controls under resting and photic stimulation (PS) conditions.
Main Methods:
- Localized proton magnetic resonance spectroscopy (¹H-MRS) was employed.
- Metabolite levels were measured in the occipital visual cortex.
- Measurements were performed in the dark (resting state) and during PS.
Main Results:
- KSS patients demonstrated significantly higher resting-state lactate levels compared to controls.
- Healthy subjects showed an immediate increase in lactate during PS, returning to baseline with sustained stimulation.
- KSS patients did not exhibit a significant lactate elevation in response to PS.
Conclusions:
- Elevated visual cortex lactate is a metabolic hallmark of KSS.
- The blunted lactate response to PS in KSS patients suggests impaired visual cortex energy metabolism.
- ¹H-MRS is a valuable tool for assessing visual cortex metabolic dysfunction in mitochondrial disorders.